Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
From: "Arash Partow" <arashp AT hotmail DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: shutdown( socket, SHUT_WR ) - unexpected behaviour
Date: Tue, 04 May 2004 06:37:11 +0000
Mime-Version: 1.0
Content-Type: text/plain; format=flowed
Message-ID: <BAY9-F40V9Zghpvafmj0000c44a@hotmail.com>

Hi,

Just out of curiosity, if one were to do:

shutdown(sck,SHUT_WR)


which means as far as I understand it "stop all send reqs made to sck",
how would one reopen the sck so that you could make send reqs again?

Is that even possible or do you have to reestablish the connection
again from scratch?

I've been looking at the man pages for shutdown on linux and netbsd
and they don't say anything about how you can reverse this effect.

Any ideas anyone?


Regards


Arash

__________________________________________________
Be one who knows what they don't know,
Instead of being one who knows not what they don't know,
Thinking they know everything about all things.
http://www.partow.net


>>I've tried your application and I'm not able to reproduce your problem.
>>The shutdown call does not influence sending the buffered data apparently.
>
>Thanks for info.
>
>>I've tested with Cygwin 1.5.9 and with a recent snapshot on XP SP1.
>>What's your system?
>
>Cygwin 1.5.9, Win2kSP2.  I made additional test using winsock directly
>and got the same buggy result.  So it doesn't look like bug in cygwin,
>but rather in windows or some 3rd party app that is messing with the
>sockets (e.g. NIS).  I found similar bugreport in MS KB298871, but it's
>marked as WinCE only:
>
>http://support.microsoft.com/default.aspx?scid=kb;en-us;298871
>
>"If an application calls shutdown() to disable only sending from the
>socket, later attempts to read data sent to that socket will result in
>only portions of the data being received."
>
>
>Can somebody with Win2k box compile and run prog from my previous mail?
>I would like to know if it behaves incorrectly only on my system, or on
>Win2k in general:
>
>http://cygwin.com/ml/cygwin/2004-05/msg00013.html
>
>$ g++ ShutdownTest.cpp -o ShutdownTest && ./ShutdownTest.exe
>No output will mean that shutdown bug is present.
>
>
>> > 1. I suppose that shutdown(sd,SHUT_WR) does not force unflushed buffers
>> > out (i.e. discards them).  Am I right?
>>
>>It doesn't flush, but it also doesn't stop the data already buffered
>>from being sent.  It's only purpose is to disallow further send calls on
>>the socket.
>
>Yes, it works this way in practice (to have other reference, I've just
>tested in on FreeBSD).  I was unsure only because unix documentation I
>found was silent about this.  The only place I found now that declares
>it clearly is MSDN:
>
>http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winsock/winsock/shutdown_2.asp
>
>"If the how parameter is SD_SEND, subsequent calls to the send function
>are disallowed. For TCP sockets, a FIN will be sent after all data is
>sent and acknowledged by the receiver."
>
>Regards,
>Jacek.


.

_________________________________________________________________
Protect your inbox from harmful viruses with new ninemsn Premium. Go to   
http://ninemsn.com.au/premium/landing.asp?banner=emailtag&referrer=hotmail


--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Problem reports:       http://cygwin.com/problems.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/